1. Field of the Invention
The present invention relates to surgical tubular device designed to be temporarily introduced into cavities of living body, such as a catheter, tracheal or gastric intubation or sounding tube, cystoscope and the like, and a method of manufacturing same.
2. Description of the Prior Art
Until now, surgical tubular devices designed to be temporarily introduced into cavities of the living body have been manufactured from rubber or from highly plasticized polyvinylchloride, or from other similar hydrophobic polymers impermeable for water and aqueous solutes. Such polymers are very different, from the physical standpoint, from living tissues. Their surface has a comparatively high coefficient of friction with respect to mucous membranes; thus, surgical devices used hitherto often hurt the tissues. To avoid this, they often have to be lubricated before use. Infection hazard is thereby increased.
Hydrophobic catheters, intubation sounds and the like cannot absorb drugs which would then gradually diffuse into the surrounding mucous membrane. It was therefore suggested to provide such hydrophobic tubular devices with a thin layer of sparingly cross-linked glycol methacrylate polymer having a water sorbtion usually about 40% by weight, and thus capable to absorb water-soluble drugs. The main drawback of such coatings is that an intermediate layer must be formed first on which the hydrogel is laid by cross-linking polymerization of a monomer mixture. The intermediate layer has a swelling capacity lower than the outer hydrogel layer and simultaneously a good adhesion to rubber of plasticized PVC, otherwise the hydrogel layer would easily separate. The tenacity and elasticity of cross-linked ethyleneglycol methacrylate polymers is comparatively low and their layer must not be too thick. Thereby the ability to incorporate a sufficient amount of drugs is rather limited.
It has been already suggested to manufacture plain tubes from swelled copolymers of acrylonitrile with acrylamide, said tubes being provided with highly slippery surface layer. Simple tubes of this kind cannot be, however, directly used as intubation or sounding tubes or catheters because of its surface slipperyness and lack of strength, but can form rather a starting raw material for the surgical tubular device of the invention.